This invention relates generally to the field of drywall compounds, also known as joint compounds, wall repair compounds, taping compounds, or mud, typically used to conceal joints or repair defects in gypsum wallboard panels. More particularly, this invention relates to a rapid setting compound and method of application, wherein the compound is applied in a pliable putty form and then rapidly cures or hardens to create a surface that conceals the joints or defects and can be sanded and painted.
Known drywall compounds typically include a filler material and a binder that are mixed with water. Conventional fillers include calcium carbonate, calcium sulfate dehydrate (gypsum) and calcium sulfate hemihydrate (plaster of Paris), and are provided as pre-mixed compounds (water already added) or setting-type compounds (dry powders to which water is added on site). The compound is applied to the drywall panels using a trowel, putty knife or similar tool, is allowed to harden and then sanded, successive coats are applied as needed, each coat being allowed to harden and sanded before the next coat is applied, then painted. Curing or setting time after application to the surface is an important factor to optimize, with faster curing times being desirable, especially in repair situations. Conversely, the compound cannot cure too rapidly, as this precludes preparing large batches of wet compound which would then harden before it can be applied. Most commercial drywall compound products have a cure time of 4 to 8 hours, although some faster setting compounds will cure in 1 to 2 hours. Even this shorter cure time is not optimal for spot applications, such as might be performed in response to a builder's punch list in new construction or by a homeowner in making a repair.
It is an object of this invention to provide a drywall compound and method of application wherein the compound remains pliable for several hours after preparation yet cures within minutes after application to a create a hard body and surface that is able to be sanded and painted, or to receive successive coats of compound as required to build a thicker body.